HHH-2614 caused LOB columns specified without a length to be exported with length 255 when using a Derby database. With this fix, the length is no longer exported for LOB columns, enabling Derby to set the default length to 2M-1 bytes. If a length is specified it will be ignored, so if you want a LOB column with a non-default length, then you will have to write the DDL yourself.

I am trying to get a hold of a sources jar for 3.6.6 from the Nexus repository at https://repository.jboss.org/nexus/. I can see an artifact for 3.6.5.Final but not 3.6.6.Final under the org.hibernate group hibernate-core artifact.